1. Technical Field
The present invention relates generally to optical lens, and more particularly to a zoom lens.
2. Description of Related Art
With the recent development of video recording devices, such as surveillance devices or closed-circuit televisions (CCTV), the market demand of lens modules increases. In consideration of convenience of installation and serviceability, the market prefers miniature and lightweight devices which perform good video quality.
Since this kind of video recording devices shows a tendency of miniature in recent years, the size of lens modules applied therein is greatly reduced too. In addition, optical lenses in these video recording devices have to provide better optical performance to achieve higher resolution and higher contrast. Therefore, miniature, high optical performance, and zooming functionality are essential elements for lenses of video recording devices.